Don't issue a warning for one-column CSVs.
Don't issue a warning for one-column CSVs.

ranjan1990/mlpack,ajjl/mlpack,palashahuja/mlpack,ranjan1990/mlpack,lezorich/mlpack,ranjan1990/mlpack,lezorich/mlpack,stereomatchingkiss/mlpack,stereomatchingkiss/mlpack,palashahuja/mlpack,ajjl/mlpack,palashahuja/mlpack,darcyliu/mlpack,ajjl/mlpack,darcyliu/mlpack,darcyliu/mlpack,lezorich/mlpack,theranger/mlpack,theranger/mlpack,theranger/mlpack,stereomatchingkiss/mlpack